Yes, a friend of mine has introduced me to the f628. Looks to be cheaper and much more versitile than the f84. I am going to move to this for the small number of units I have to make. thanks ----- Original Message ----- From: "Jinx" To: Sent: Wednesday, February 27, 2002 2:48 AM Subject: Re: [PIC]:Watchdog timer reset in 16f84 > > You have to put CLRWDT instructions in strategic > > places in your code > > By "strategic", Tony means that the CLRWDT instruction > must be executed within the time period of the WDT. If, > for example, you have no pre-scaler on the WDT it will > reset the PIC every 18ms. To avoid that, you must make > sure by some means in your software that the CLRWDT > is executed before each and every expected WDT reset. > > How you do that depends on the structure of your program. > Although I haven't done this myself, you could use the TMR0 > interrupt to call a routine with CLRWDT in it if you do not > have convenient looping withing the program otherwise. As > you also wish to have a reset in case of a fault, you should > be able to arrange things so that the CLRWDT is not executed > in that case. > > Using the pre-scaler with WDT will increase the reset period > to a little over 2 seconds, which may or may not be useful to you. > Note though that the pre-scaler has to be assigned to either > WDT or TMR0 and that the division ratio of the pre-scaler is > not the same with WDT as it is with TMR0 > > And you'll know that the F628 is preferable to the F84 if you're > getting new stock > > -- > http://www.piclist.com hint: The list server can filter out subtopics > (like ads or off topics) for you. See http://www.piclist.com/#topics > > -- http://www.piclist.com hint: The PICList is archived three different ways. See http://www.piclist.com/#archives for details.